ceph-csi/vendor/google.golang.org/protobuf/proto/wrapperopaque.go
dependabot[bot] ca1ccdd9bf rebase: bump google.golang.org/protobuf from 1.35.2 to 1.36.0
Bumps google.golang.org/protobuf from 1.35.2 to 1.36.0.

---
updated-dependencies:
- dependency-name: google.golang.org/protobuf
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
2024-12-19 06:43:41 +00:00

81 lines
2.5 KiB
Go

// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package proto
// ValueOrNil returns nil if has is false, or a pointer to a new variable
// containing the value returned by the specified getter.
//
// This function is similar to the wrappers (proto.Int32(), proto.String(),
// etc.), but is generic (works for any field type) and works with the hasser
// and getter of a field, as opposed to a value.
//
// This is convenient when populating builder fields.
//
// Example:
//
// hop := attr.GetDirectHop()
// injectedRoute := ripb.InjectedRoute_builder{
// Prefixes: route.GetPrefixes(),
// NextHop: proto.ValueOrNil(hop.HasAddress(), hop.GetAddress),
// }
func ValueOrNil[T any](has bool, getter func() T) *T {
if !has {
return nil
}
v := getter()
return &v
}
// ValueOrDefault returns the protobuf message val if val is not nil, otherwise
// it returns a pointer to an empty val message.
//
// This function allows for translating code from the old Open Struct API to the
// new Opaque API.
//
// The old Open Struct API represented oneof fields with a wrapper struct:
//
// var signedImg *accountpb.SignedImage
// profile := &accountpb.Profile{
// // The Avatar oneof will be set, with an empty SignedImage.
// Avatar: &accountpb.Profile_SignedImage{signedImg},
// }
//
// The new Opaque API treats oneof fields like regular fields, there are no more
// wrapper structs:
//
// var signedImg *accountpb.SignedImage
// profile := &accountpb.Profile{}
// profile.SetSignedImage(signedImg)
//
// For convenience, the Opaque API also offers Builders, which allow for a
// direct translation of struct initialization. However, because Builders use
// nilness to represent field presence (but there is no non-nil wrapper struct
// anymore), Builders cannot distinguish between an unset oneof and a set oneof
// with nil message. The above code would need to be translated with help of the
// ValueOrDefault function to retain the same behavior:
//
// var signedImg *accountpb.SignedImage
// return &accountpb.Profile_builder{
// SignedImage: proto.ValueOrDefault(signedImg),
// }.Build()
func ValueOrDefault[T interface {
*P
Message
}, P any](val T) T {
if val == nil {
return T(new(P))
}
return val
}
// ValueOrDefaultBytes is like ValueOrDefault but for working with fields of
// type []byte.
func ValueOrDefaultBytes(val []byte) []byte {
if val == nil {
return []byte{}
}
return val
}